The effects of the two kinds of optical waveguide structures on the field of view and the size of waveguides are analyzed, and the waveguide structure and thin films are optimized. With the TFCalc software, the p polarized beam splitting films in the waveguide are designed. With the choice of H4 and MgF2 as the respective high and low refractive index materials and with the combination of the Needle and Variable Metric methods, the film system is optimized. In the wave band of 450~600 nm, the average reflectivity of the p polarized beam splitting films is 30.1% at an incident angle of 25° and is less than 5% at angles of incidence from 50° to 80°. The above film fulfills the requirements for the firmness testing.